Conventionally, in a self-ballasted lamp using LED elements as its light source, a substrate having LED elements mounted thereon is attached to one edge side of a radiator, and a globe is attached in a manner that the globe covers the substrate, a cap is attached to the other edge side of the radiator via an insulative member, and a lighting circuit is accommodated inside the insulative member.
For example, as described in Japanese Laid-open Patent Publication No. 2009-37995, the radiator is made of die-casted aluminum and is integrally molded so that heat of the LED elements can be efficiently conducted and radiated to the outside.
However, the shape of the radiator is restricted in a range of forms moldable by an aluminum die-casting method if the radiator of the self-ballasted lamp is made of die-casted aluminum, there is a limitation in adopting an excellent shape in regard to heat radiation performance, and there is a problem that further improvement of heat radiation performance is difficult.
In addition, where the radiator of a self-ballasted lamp is made of die-casted aluminum, other problems arise that the production cost is increased, and the weight is increased. Since the load given to lighting equipment in which the self-ballasted lamp is used is increased if the weight of the self-ballasted lamp is heavy, still another problem arises that an attempt must be made to increase the supporting strength of the lighting equipment.
The present invention was developed in view of such points, and it is therefore an object of the invention to provide a self-ballasted lamp which has a high heat radiation performance, is lightweight and inexpensive, and lighting equipment using the self-ballasted lamp.